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#ifndef MESSAGE_FILTERS__PASS_THROUGH_HPP_
#define MESSAGE_FILTERS__PASS_THROUGH_HPP_

#include <memory>
#include <utility>
#include <vector>

#include "message_filters/simple_filter.hpp"

namespace message_filters
{
/**
 * \brief Simple passthrough filter.  What comes in goes out immediately.
 */
template<typename M>
class PassThrough : public SimpleFilter<M>
{
public:
  typedef std::shared_ptr<M const> MConstPtr;
  typedef MessageEvent<M const> EventType;

  PassThrough()
  {
  }


  template<typename F>
  PassThrough(F & f)  // NOLINT(runtime/explicit)
  {
    connectInput(f);
  }

  template<class F>
  void connectInput(F & f)
  {
    incoming_connection_.disconnect();
    incoming_connection_ =
      f.registerCallback(
      typename SimpleFilter<M>::EventCallback(
        std::bind(
          &PassThrough::cb, this,
          std::placeholders::_1)));
  }

  void add(const MConstPtr & msg)
  {
    add(EventType(msg));
  }

  void add(const EventType & evt)
  {
    this->signalMessage(evt);
  }

private:
  void cb(const EventType & evt)
  {
    add(evt);
  }

  Connection incoming_connection_;
};

}  // namespace message_filters

#endif  // MESSAGE_FILTERS__PASS_THROUGH_HPP_
